1. Field of the Invention
This invention relates to an emergency exit system, and in particular to an emergency exit system for use in a helicopter or other aircraft.
While the system of the present invention was designed specifically for use in an aircraft, it will be appreciated that the system could be used in other vehicles such as trains or buses.
2. Discussion of the Prior Art
Applicants"" international patent application PCT/CA98/00739 filed on Jul. 31, 1998 discloses an emergency exit system of generally the same type as disclosed herein. As mentioned in the PCT application, vehicle accidents occurring in water have a lower survival rate than accidents occurring on land. In water accidents, the aircraft usually sink very rapidly, either in an upright or inverted position. Underwater conditions are drastically different from land based conditions. Visibility is reducedxe2x80x94the majority of people can see only 1.5 meters underwater and 3.1 meters in the best lit conditions. Survivors of a crash or forced landing must depend on their breath-holding ability to make a successful escape. Generally, a person""s breath-holding ability is reduced 25-50% in water under 15xc2x0 C . Maximum breath-holding time can be as short as 10 seconds. Survivors are often disoriented due to the sudden immersion in water, loss of gravitational references, poor depth perception, nasal inhalation of water and darkness. Disorientation is magnified when the vehicle is inverted. Under the latter condition, finding a handle to jettison an escape door or window, which is a simple procedure to execute in an upright position on dry land, can be a most challenging task even if the handle is only a few centimeters away from the survivor""s hand.
Usually handles for opening escape doors or windows are small, and are positioned between knee and chest level. The various positions, i.e. locked or secured and released, would not be obvious to the survivor unless he or she is familiar with the particular escape system. Existing escape hatches for aircraft are difficult to replace or reinstall once jettisoned. Consequently, even persons being trained as aircrew do not receive practice in emergency escape procedures. Most existing mechanisms are adapted to remove an entire door or window, including the frame, requiring a complicated jettison mechanism, which is not always dependable. Most escape hatches are operated by movement of a single handle in one direction only. Thus, valuable time and effort can be wasted in attempting to operate the hatch release mechanism. Moreover, existing systems do not provide feedback, i.e. there is no visual or other indication that the door, window or hatch as been successfully jettisoned.
GB-A-761 627 and U.S. Pat. No. 3,851,845 disclose systems for the jettisoning of aircraft canopies or doors which are inappropriate for use in a door or window release. The U.S. patent teaches the use of lever or a lever and a handle combination for releasing a door. When submerged in water such a system could be difficult to operate, particularly when it is necessary to operate a handle and a separate lever to effect release of the door.
An object of the present invention is to provide an emergency exit system of the type which includes at least one easily accessible actuator adapted to operate in more than one direction to affect release of a Window or door panel to provide an escape exit.
In applicant""s earlier invention, cables were mainly relied upon to release a panel. When repeatedly subjected to longitudinal forces, cables tend to stretch. Accordingly, while cable are still used in the present case they play a smaller roll in operation of the exit system, namely to release a spring operated drive which effects panel release.
Accordingly, the present invention relates to an emergency exit system including a panel for closing in an opening in a vehicle wall comprising a plurality of spaced apart panel latch means for releasably latching said panel in said opening; release means for simultaneously releasing all said panel latch means, drive means for operating said release means; drive latch means for releasably retaining said drive means in an inoperative condition; and principal actuating means rotatable in said vehicle wall proximate said opening for releasing said drive means, whereby rotation of said principal actuating means causes said drive means operate said release means to simultaneously release all said panel latch means.
The use of an opposed auxiliary release handles on the inside and outside of the vehicle provides an alternate means for operating the panel latch means, and permits the operation of the panel latch means by a rescuer from the exterior of the vehicle.
The invention described herein also includes light means in said actuating means which provide a visual aid for locating the escape panel, and for positively indicating that the panel has been jettisoned. The light means is adapted to operate in a steady (always on) or a strobe mode. In one mode, the light means acts as a locating aid, and in the other mode, the light means provides a positive indication that the panel has been jettisoned.
The provision of a simple mechanism for replacing the panel in the opening encourages practice of escape procedures before an emergency situation arises. Whereas it is difficult and time consuming to replace existing escape hatches, once released, using the system of the present invention, the panel can be re-mounted in the opening typically in 5 to 10 seconds.